Power Supply Unit (PSU)

A Power Supply Units – which have received the acronym PSU – is the device that makes sure that your laptop or desktop can reshape the 230v in the wall connector into something your laptop or desktop computer can use. Without power, we don't get far, which is why we always need a power supply with a computer – whether it's a desktop or a laptop in question.>

Laptop power supplies

A portable power supply is also called an external power supply. The power supply is not inside the machine itself, but instead it is external, and has one cable to connect power supply to the laptop, as well as one cable to connect the power supply to the power grid. 
The cable from the power supply to the power outlet is most often removable and can therefore easily be replaced in case of problems with charging your laptop. Therefore, always start by replacing this, if you run into problems charging a machine. 

If this doesn't work, the power supply itself and the laptop jack are the next in line. This is a unified device, so a replacement here should include the entire power supply. 

45w, 65w, 90w, 120w – what do I need?

Laptops as well as desktop computers with external power supplies run at a number of different power levels(watts). Some need more, while others need less. Usually, machines with dedicated graphics cards should always have 90w or more, and machines without dedicated graphics cards can most often get by with 65w or less. 

If you're looking for a power supply for a specific machine, it's always important to make sure the connector fits and that the power (wattage) is at the right level. Otherwise, the machine may not start or the battery will burn off faster. 
A good start is always to go to the manufacturer's website and look up the machine. Here, in the vast majority of cases, you will be able to see how much power power the manufacturer recommends for the machine. 

Power supply for desktop computer

In a desktop computer, we are most often dealing with internal power supplies. This means that if the power supply does not work, the machine will need to be opened up in order for the power supply to be replaced by a new one. Here it is also a good idea to first test the cable from the machine to the power outlet, if you suspect a power supply failure. 

When it comes to desktop computers, however, there are also exceptions, since several of the smaller sizes simply do not have room for an internal power supply and therefore have to use an external power supply instead – just like a laptop. You can expect any machine with Tiny, USFF, or USDT in the name to have an external power supply.

Power supply / charging cable for mobile phone and tablet

Your mobile or tablet must of course also use power. When it comes to tablets or mobiles, a charging kit is also referred to as being a power supply, but the correct term is actually a charging cable and a charger. It is the combination of these two that is needed to be able to charge, for example, your new iPhone or Samsung Galaxy. 

The most important thing is to get a cable that fits in the phone. Most newer Android phones use USB-C, while iPhones use lightning cables. Chargers are easier to use for different machines as they have a normal USB connector and can therefore be used with any charging cable. In the past, you had to be careful not to use the charger for your tablet for your mobile phone, because tablet chargers were running at a higher voltage (ampere). However, now all newer phones and tablets can adjust how much of the voltage they take advantage of when charging, so that's no longer a concern. Some smartphones can actually be charged faster with a tablet charger – without any negative effect.

My power supply connector is a little "off", but it still works – there's nothing wrong with that, is there?

Unfortunately, there are a lot of people who use power supplies or charging cables where the cable around the connector is disconnected or outright disintegrating. Many people think that if the phone still charges, then there can be nothing wrong with it. However, an unprotected wire is a major fire damage and should therefore be changed as soon as the cord can be seen from inside the cable. You should also always charge your phone or tablet during the daytime, as with all electronics, there is a chance that the device can short-circuit, and charging your electronic devices at night can therefore be a fire hazard.